Unpacking Posture – Part 2

Dynamic posture in horses: The interplay between body position and movement

by Kevin K. Haussler, DVM, DC, PhD

in collaboration with Caroline Lindsay, BSc(Hons), PGCert, MSFC Dip, AdvCertVPhys, CertEdVPT; and Alissa Mayer, BSc(Equine), EHSE-C

Dynamic posture reflects the intricate interplay of biomechanics, balance, and movement during both unridden and ridden exercise. In Part 1 of this blog series, we talked about static posture. In Part 2, we explore some of the attributes that contribute to dynamic posture in horses. Part 3 will examine rider-horse interactions.  

Defining dynamic posture

Dynamic posture refers to the organization and control of the body in motion. Like static posture, dynamic posture is characterized by the position and alignment of the body segments with respect to the force of gravity and the surrounding environment, as well as internal nociceptive and mechanoreceptive signaling.

Dynamic posture is often closely linked to conformation and conformational faults. A horse with an angular limb deformity is likely to have an aberrant static limb posture at rest and an associated postural deviation during locomotion. Similarly, deviations in static posture often carry over into postural changes observed during movement.

Movement versus posture

There is some disparity between the concepts of how a horse holds itself during movement (i.e., dynamic posture) and descriptions of the movement itself (e.g., stride length, joint range of motion, or ease of movement). Examples of dynamic posture include an elevated head and neck position or lateralized tail carriage while a horse is trotting in hand. Descriptors of an elevated head and neck position might include the distance that the head is held above the height of the withers or the amount of thoracolumbar extension (i.e., body position).

Conversely, descriptions of movement might include fluency, balance, rhythm, symmetry, or engagement. The lack of clear or often misinterpreted definitions for body position (i.e., posture) versus movement patterns (e.g., kinematics) has led to general confusion and muddled communication both within and between professions. Within cursorial animals, there are typically set, or predictable patterns of limb and axial skeleton movement based on specific anatomical features and neuromuscular activation. These repetitive movement patterns form the basis of gait analysis and lameness detection.

Gait evaluation includes stride length, cadence, and suspension with smooth, balanced transitions between gaits. Engagement of the hindquarters and core musculature are characterized by impulsion and stability throughout the neck, trunk, and pelvic regions. Signs of fluency, collection, and self-carriage are all qualitative attributes of posture (i.e., body position), whereas muscle development (i.e., conformation), impulsion (i.e., neuromuscular engagement, strength), or joint stiffness (i.e., reduced range of motion) are not direct postural characteristics but are important contributing factors to how a horse might hold its body during unridden or ridden exercise.

Qualitative attributes used to describe movement patterns (but not posture) may include a few of the following characteristics:

  • Global – fluidity and ease of movement, stability
  • Consistency of movement patterns – fluency, timing, consistency
  • Gait symmetry – stride length, joint range of motion, quality of transitions
  • Vertebral column – smooth, consistent, supple movement
  • Pelvic limbs – hindquarter engagement, impulsion
  • Limbs – cadence, coordination, loading and unloading rates, amount of weight bearing
  • Hooves – timing of break over, trajectory during swing phase

Assessing dynamic posture

Dynamic posture reflects the horse’s ability to maintain equilibrium, rhythm, and stability while in motion. Postural assessment requires keen observational skills and a working knowledge of equine behavior, balance, and biomechanics. Dynamic posture requires the horse to constantly adjust and adapt its body to maintain balance, coordination, and efficiency in response to changes in position, speed, direction, and external forces. How the horse holds itself during these changes forms the basis for assessing dynamic posture.

The position of individual body segments and the interaction between adjacent segments are viewed from the front, side, and rear. Dynamic posture may vary significantly depending on the horse’s age and breed, the course of travel (e.g., straight line vs circle), the speed or gait (e.g., working versus extended trot), and the presence of a rider (unridden versus ridden exercise).

Here are some specific physical parameters used to assess a horse’s dynamic posture:

  • Head and neck carriage – head height above the ground, head and neck positions relative to the rest of the body, axial alignment, consistency of head carriage throughout various movements or transitions
  • Trunk – aberrant dorsal or ventral curvatures, axial alignment, relative position and movement of vertebral segments, vertical displacement of osseous or soft tissue landmarks
  • Pelvis – amount of lumbosacral flexion and extension, left-right motion asymmetries
  • Tail – tail carriage (e.g., extended, held consistently toward the left or right)
  • Limbs – foot placement, joint angulations, alignment of limb segments during the stance or swing phase
  • Hooves – initial foot contact (e.g., medial-lateral, toe-heel) and timing of footfall
  • Global – overall position and alignment of body segments, straightness

Ideal dynamic posture

A detailed evaluation of the local, regional and global alignment of body segments provides insights into the consistency of the observed postural tendencies. Ideal dynamic posture is characterized by a harmonious alignment of body segments and overall body position during movement.

To assess dynamic posture, the horse should be calm and relaxed. The head is typically carried in a relaxed, neutral position, with the poll held slightly higher than the withers while at liberty. When viewed from the side, the head and neck should form a smooth, continuous curve that can be followed through the trunk, pelvis, and tail. Different induced head and neck positions are expected to directly affect dynamic posture within the thoracolumbar and pelvic regions. Vertical displacement of the head, withers, and pelvis should be longitudinally symmetric and synchronized to limb movements. The dorsal midline of the trunk should be relatively straight with fluid motion noted within the thoracic and lumbar vertebral regions. The pelvis should have symmetric left-right vertical and horizontal displacement when viewed from behind. The tail should be carried vertically and have symmetrical movement from left-to-right. The limbs should be positioned uniformly and squarely under the body at different gaits and directions of travel.

Effects of dynamic posture

Dynamic posture may significantly impact the performance, soundness, and longevity of horses. A horse with ideal dynamic posture for a specific athletic discipline and training level moves with efficiency, power, and grace. Deviations from ideal dynamic posture, such as asymmetries or altered limb placement, can compromise performance, predispose to overuse injuries, and hinder the horse’s ability to excel in their chosen discipline.

Factors to consider

Dynamic posture is fluid and responsive, constantly adapting to the demands of different activities, rider cues, and terrains. Each of the following factors plays a role in shaping the horse’s muscle development, strength, and coordination, all of which directly impact how the horse holds its body during movement.

  • Conformation – Conformational faults often directly impact static posture, which carries over into dynamic postural assessment.
  • Temperament, emotional status – Mental alertness and behavior have direct influences on how a horse holds its head and neck or positions other body segments during movement.
  • Age, training level – Younger horses and those with lower training levels may not have fully developed body awareness (i.e., mechanoreception) or neuromuscular engagement (i.e., strength, coordination), which directly impact dynamic posture.
  • Athletic discipline and training – Different activities may require different dynamic postures (e.g., Thoroughbred versus Standardbred racing), and various training methods or techniques often create learned or habitual alterations to posture.
  • Fitness, conditioning – Acute fatigue and weakness often directly impact posture.
  • Pre-existing injuries – Residual tissue damage may produce signs of weakness, pain, or altered joint range of motion, which can impact dynamic posture.
  • Tack and equipment – Ill-fitting or improperly applied bit or saddle often induce avoidance responses and a compromised posture.
  • Footing and terrain – Firm versus uneven or deep footing directly affects how a horse holds itself. Similarly, horses have obvious differences in posture as they travel uphill versus downhill.

Pain and dynamic posture

Pain can significantly disrupt dynamic posture in horses, leading to compensatory movement patterns, decreased joint range of motion, and diminished performance. How a horse uses its limbs, head and neck, trunk, and pelvis during different gaits and athletic activities provides clues to potential sources of pain or lameness. Whether stemming from musculoskeletal injuries, dental issues, or underlying health conditions, pain alters a horse’s movement patterns. 

Advanced techniques such as video gait analysis and the use of inertial sensors or artificial intelligence offer valuable tools for assessing the intricacies of dynamic posture. Recognizing and addressing pain-related issues is essential for restoring ideal dynamic posture and promoting a horse’s overall well-being.

Asymmetry and dynamic posture

Functional and structural asymmetries directly impact how a horse uses and positions its body during movement. Functional asymmetries can be caused by physiological mechanisms, such as cerebral dominance (i.e., sensory or motor laterality) or pathologic conditions associated with pain (i.e., antalgic gait), muscular hypertonicity (i.e., increased muscle tone) or altered mechanoreception (e.g., incoordination, ataxia). Any functional disturbance can have a direct and immediate effect on dynamic posture.

Asymmetric movement patterns can be categorized as adaptive or maladaptive. Unweighting a limb due to acute distal limb pain is an adaptive response which serves to protect the site of injury and reduce further tissue damage. However, if the associated deviated posture and antalgic gait persists long after the initial, inciting injury has healed, then this is considered to be a maladaptive response – the response to injury is no longer a physiologic or protective mechanism, but rather has become a disease entity unto itself.

Structural asymmetries can either be relatively short-lived and resolve with focused treatment (e.g., a bowed tendon, muscle atrophy) or more permanent due to significant tissue damage (e.g., displaced fracture, advanced osteoarthritis). Like conformational defects, structural asymmetries are expected to directly impact dynamic posture.

In closing…

Dynamic posture serves as a hallmark of equine athleticism, reflecting the interplay of biomechanics, neuromuscular conditioning, and fascial support. By defining dynamic posture, exploring assessment techniques, and understanding contributing factors, we gain valuable insights into how and why a horse holds its body as it does during movement. Through attentive observation and collaborative care, we can strive to optimize dynamic posture and improve the overall well-being of horses.

Is this the way you assess dynamic posture?

When do you assess dynamic posture?

Read all 3 parts of this blog, then on May 30th at 3 pm MDT, join Dr. Haussler and his guest collaborators – veterinary physiotherapist, saddle fitter, and graduate sports therapist Caroline Lindsay and Certified Equine Hanna Somatics® Educator Alissa Mayer – to discuss the important topic of posture. 

Registration at vetspine.org/community-gatherings/

Interested in learning more?

Resources

Byström A, Clayton HM, Hernlund E, Roepstorff L, Rhodin M, Bragança FS, Engell MT, van Weeren R, Weishaupt MA, Egenvall A. Asymmetries of horses walking and trotting on treadmill with and without rider. Equine Veterinary Journal. 2021 Jan;53(1):157-66.

Clayton HM, MacKechnie-Guire R, Hobbs SJ. Riders’ Effects on Horses—Biomechanical Principles with Examples from the Literature. Animals. 2023 Dec 15;13(24):3854.

Lashley MJ, Nauwelaerts S, Vernooij JC, et al. Comparison of the head and neck position of elite dressage horses during top-level competitions in 1992 versus 2008. Vet J 2014; 202: 462-465.

Lesimple C, Fureix C, Menguy H, Hausberger M. Human direct actions may alter animal welfare, a study on horses (Equus caballus). PLOS One. 2010 Apr 28;5(4):e10257.